Users of a packet switched network are commonly connected to the network by means of modem-router units. A modem-router unit is commonly in between the user equipment (such as telephones, personal computers, facsimile machines, televisions, etcetera) and the actual network entities of the packet switched network. The modem-router unit often comprises a modem for conversion of communication signals from the external to the internal network, a router for internally delivering data traffic to the correct user equipment, a firewall for protection of the internal network behind the modem-router unit from the external network, a switch or hub for use by the internal network, and various other optional logical or physical entities.
For actual communication with the network and the user equipment, the modem-router comprises a communication unit, often comprising a wireline communication unit and a wireless communication unit. The wireline communication unit handles all wireline communication, amongst others the communication between the modem-router unit and the packet switched external network, but also wireline connections between the modem-router unit and computers and other entities on the internal network. The wireless communication unit or wireless access point enables user equipment and entities of the internal network to set up a wireless connection with the modem-router unit. This enables, for example, users to connect to the modem-router unit and to the external packet switched network with a laptop and a wireless local area network (WLAN, according to standard IEEE 802.11) connection.
From time to time, and for many different reasons, a physical connection between the modem-router unit and the external packet switched network entities may fail, or may be insufficient for enabling proper communication. As a result of the failing data connection, the entities present on the internal network that rely on communication with the packet switched external network will not be available to the user. For example, the user will not be able to make a telephone call with his voice-over IP phone, a website or other public services of the user running on a server on the internal network will not be available, web related services on the television of the user may be available, and many other internet services such as e-mail or server will not be available to the user.